Pulmonary thromboembolism with computed tomography defined chronic thrombus is associated with higher mortality

With the advancement of computed tomography pulmonary angiography, differentiating between acute and chronic thrombus in pulmonary embolism has become more feasible. However, whether pulmonary embolism with chronic thrombus contributes to a higher mortality than pulmonary embolism with acute thrombus remains undetermined. Additionally, the clinical features of patients with chronic thrombus are largely unknown. Herein, we aimed to investigate the incidence and outcomes of patients with pulmonary embolism and chronic thrombus. This retrospective study included patients with pulmonary embolism from 2008 to 2016 at National Cheng Kung University Hospital. After excluding patients with tumor emboli or other etiologies and a lack of computed tomography images, we identified 205 patients with acute thrombus and 58 patients with chronic thrombus. Patients with chronic thrombus initially presented mainly with dyspnea, and the etiology was not related to recent surgery. Patients with chronic thrombus had a significantly higher incidence of elevated right ventricular systolic pressure detected by echocardiography and a higher incidence of subsequent events due to residual pulmonary embolism. Despite no differences in clinically recurrent pulmonary embolism, patients with chronic thrombus presented with a higher risk of all-cause and pulmonary embolism-related mortality than patients with acute thrombus. Chronic thrombus (hazard ratio: 2.03, p = 0.03), simplified pulmonary embolism severity index, anticoagulant use, and body mass index were the independent factors for all-cause mortality. Our findings suggest that using computed tomography pulmonary angiography for identifying patients with pulmonary embolism and chronic thrombus, which was associated with a higher risk of mortality, is pivotal for early intervention in addition to anticoagulant use.